1. Field of the Invention
The present invention relates to recording and/or reproducing information, for effectively processing a still picture, and more particularly, to a recording medium for storing virtual deletion information for preventing file extent information from excessively increasing when some of a data file is deleted by a user's request, and recording and/or reproducing method and apparatus therefor.
2. Description of the Related Art
FIG. 1 shows a connection structure for various kinds of information in a moving picture and moving picture data, in recording/reproducing audio and/or video data on a recordable and/or rewriteable recording medium, specifically, a digital versatile disk (DVD), and more precisely, it illustrates the relationship between program chain (PGC) information 11 for treating data logically, moving picture information 12 including video object (VOB) information, and a moving picture data file 13 in which actually compressed audio/video (A/V) data are recorded in VOB units.
First, terms used throughout the specification will now be described. Supposing a movie was recorded in first and second parts, the overall movie is a program chain (PGC) and the first and second parts are programs. Also, each program can be defined by further dividing the same into several cells called sub-units. The information in each cell can wholly or partially define a video object (VOB). In such an event, each cell is used as a basic accessing unit during reproduction, and the program and PGC are only the information for connectivity between a plurality of cells.
Also, since data is actually sub-divided into video object units (VOBUs) and recorded in a moving picture data file, the VOB information includes various kinds of information relating to the VOBU data, that is, VOBU #1, VOBU #2, . . . and the VOB data in the moving picture data file is accessed by the VOB information. Here, the VOB data is used as a random access unit of a disk recording/reproducing apparatus. The VOBU is based on a single GOP (Group of Pictures) in the case of an MPEG (Moving Picture Experts Group) video, and audio data corresponding to video data is collected, that is, A/V data is multiplexed into sectors, to constitute a VOBU.
The data format shown in FIG. 1 is concerned with the moving picture, in which the unit of actual data, the VOB, comprises moving picture data for a fixed period of time. Synchronization or encoding of A/V signals is performed in units of VOBs. However, in the case of a still picture, each VOB constitutes a still picture. When a VOB is designated in a cell structure, a cell is necessary for each still picture. Thus, as more still pictures are recorded, more information is added.
Generally, data errors may be generated if data is recorded on a recordable disk a predetermined number of times. Thus, there is a limit in the number of times for rewriting data on a disk. All information is stored in the memory of a controller for controlling the system for the purpose of limiting the number of recording times and rapidly accessing data. However, as described above, in the case of a still picture, if the amount of information is increased, much time is required for reading the information. Also, there is a limit to the amount of information that can be stored in a memory with a limited size. Accordingly, it is not possible to record a large-capacity still picture.
In a two-dimensional recording medium such as a disk, a file may be distributed in physically fragmented spaces to then be recorded, and information which connects the scattered areas is recorded in a file system as file extent information. File extent information is information for logically connecting a file having the scattered areas and generally represents the scattered areas sequentially as start positions and lengths of data. Referring to FIG. 2, for example, a file is distributed and recorded in two parts, each represented by a start position and length of data in the file extent information. If a portion indicated by “A” shown in FIG. 2 is deleted so that the file is distributed in three parts, the amount of file extent information is increased, as shown in FIG. 3.
In other words, as shown in FIG. 3, the amount of file extent information is determined according to the level of fragmentation of a file, irrespective of the size of the file. Therefore, when a plurality of still pictures are recorded in a file, if some still pictures are deleted by a user's request, thus causing fragmentation of the file, the amount of the file extent information is sharply increased.